Li₆PS₅X (X = Cl, Br, I) argyrodites possess high ionic conductivity but with rather scattered values due to various processing conditions. In this work, Li₆PS₅X solid electrolytes were prepared by solid-state sintering or mechanical alloying and optimized with or without excess Li₂S. Solid-state sintering prefers excess Li₂S, whereas mechanical alloying prefers stoichiometric Li₂S to synthesize high-purity samples with high ionic conductivity. Solid-state sintering is also more suitable than mechanical milling for high ionic conductivity. Li₆PS₅Cl with the highest ionic conductivity among Li₆PS₅X was comprehensively characterized for electrochemical performance and air stability. MoS₂/Li₆PS₅Cl all-solid-state batteries assembled with Li₆PS₅Cl-coated MoS₂ as cathode and with Li₆PS₅Cl as solid electrolyte demonstrate high capacity and good cycling stability.

Exploration of advanced anode materials is a highly relevant research topic for next generation lithium-ion batteries. Here, we report severe lattice distorted MoS₂ nanosheets with a flower-like morphology prepared with PEG400 as additive, which acts not only as surfactant but importantly, also as reactant. Notably, in the absence of a carbon-related incorporation/decoration, it demonstrates superior electrochemical performance with a high reversible capacity, a good cycling stability, and an excellent rate capability, originated from the advantages of synthesized MoS₂ including enlarged interlayer spacing, 1T-like metallic behavior, and coupling of Mo–O–C (and Mo–O) hetero-bonds. PEG-assisted synthesis is believed applicable to other anode materials with a layered structure for lithium-ion batteries.

Garnet-type Li₇La₃Zr₂O₁₂ solid electrolytes were commonly prepared by two steps solid-state reaction method, which undergoes high temperature over 1000 °C and thus inevitable for lithium volatilization and formation of secondary phases. Here, we propose a new intergrain architecture engineering of a solution method, to avoid high temperature sintering for preparing lithium halide (LiX) coated garnet-type solid electrolytes, which contain Al and Ta co-doped Li₇La₃Zr₂O₁₂ (Li_6.75La₃Zr_1.75Ta_0.25O₁₂, LLZTO) synthesized at 900 °C with cubic structure. Owing to the increased relative density, the improved formability, and the altered ion transport mode from point to face conduction by LiX coating on LLZTO grains, LiX-coated LLZTO samples demonstrate a good Li dendrite suppression ability and a high ionic conductivity that is three orders of magnitude higher than pristine LLZTO. In another way, this result demonstrates the critical role of the grain boundaries on the ion transport for oxide superionic conductors. The present coating method provides a new strategy to prepare brittle solid electrolytes avoiding high temperature sintering.

Exploration of advanced solid electrolytes with good interfacial stability toward electrodes is a highly relevant research topic for all-solid-state batteries. Here, we report PCL/SN blends integrating with PAN-skeleton as solid polymer electrolyte prepared by a facile method. This polymer electrolyte with hierarchical architectures exhibits high ionic conductivity, large electrochemical windows, high degree flexibility, good flame-retardance ability, and thermal stability (workable at 80 °C). Additionally, it demonstrates superior compatibility and electrochemical stability toward metallic Li as well as LiFePO₄ cathode. The electrolyte/electrode interfaces are very stable even subjected to 4.5 V at charging state for long time. The LiFePO₄/Li all-solid-state cells based on this electrolyte deliver high capacity, outstanding cycling stability, and superior rate capability better than those based on liquid electrolyte. This solid polymer electrolyte is eligible for next generation high energy density all-solid-state batteries.